The present invention relates to semiconductor structures, semiconductor devices, electronic devices, and methods of making each.
It is known to implant nitrogen ions into semiconductor structures at a high dose to form an interface between a silicon substrate and a sacrificial dielectric layer to strengthen the bonding between the substrate and the dielectric layer. See C. T. Liu, Y. Ma, et al., xe2x80x9cLight Nitrogen Implant for Preparing Thin-Gate Oxidesxe2x80x9d 18 (March 1997) No. 3, New York, pp. 105-107. After implantation of nitrogen through the sacrificial dielectric layer, the layer is stripped away and another oxide is grown. The nitrogen retards oxidation, so the new dielectric layer (the gate dielectric layer) is generally less than 20 xc3x85 thick. Liu indicates that a high does is necessary to achieve the improved bonding. However, the higher the dose, the thinner the new dielectric layer. For certain semiconductor structures, a dielectric layer less than 20 xc3x85 thick is undesireable.
This known procedure adds a step to the manufacturing process because the gate dielectric layer is needed to replace the sacrificial dielectric layer that was stripped away. This procedure also does not maximize the strength of interface bonding between the silicon substrate and the gate dielectric layer that can be gained through the implantation of nitrogen. The less-than-optimal strength of the interface bonding may interfere with the flash memory application of the semiconductor structure.
The structures, devices, and processes described herein address at least some of the above-identified shortcomings.
In one aspect of the invention, a process for making a semiconductor structure comprises implanting nitrogen through a layer comprising SiO2 into a substrate comprising Si, wherein the layer is on the substrate, and wherein the layer is from about 30 xc3x85 to about 300 xc3x85 thick.
In another aspect of the invention, a process for making a semiconductor structure comprises implanting nitrogen through a layer comprising SiO2 into a substrate comprising Si, wherein the layer is on the substrate, and the layer is from about 30 xc3x85 to about 300 xc3x85 thick, and wherein the implanting causes defects; washing the semiconductor structure; and removing the defects.
In still another aspect of the invention, A process for making a semiconductor device, comprises (a) making a semiconductor structure comprising implanting nitrogen through a non-sacrificial layer comprising SiO2 into a substrate comprising Si, wherein the layer is on the substrate, and the layer is from about 30 xc3x85 to about 300 xc3x85 thick, and wherein the implanting causes defects; washing the semiconductor device with an aqueous solution comprising ammonium hydroxide; removing the defects; and (b) converting the semiconductor structure into a semiconductor device.
The present invention provides the foregoing and other features, and the advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention and do not limit the scope of the invention, which is defined by the appended claims and equivalents thereof.